Ive took my car from the gm dealer 2 weeks ago .They install 3.73 slp gear and pinion with a master install kit(every bearing and shim)also a ta girdle.

Ive made my break for about 600km.No problem at all,no noise.

Ive decide to try my new gear and i floor it.Untill 70km/h there is no problem , but after that the gear begin too do a litlle roar sound.At 100km/h you can here without a doubth and at 160km/h it roar so loud that i ve the feeling that my diif is gonna blow...

The backlash is set at 0.005(thats written on the bill) and i dont know about the pinion depth.

So what should i do???

 

please don't tell me you ripped those gears without breaking them in.

 

No i ve maid 600km of breaking.

 

Gears shouldn't whine, but most gears do end up with some type of whine. Mine whine abut after 60 but their quiet under decel. I would just take it back to the dealer and let them check it out. Since they did the job they should be able to warranty thier work... if they are a reliable dealer.